4 July 2024
Lizard snake venom avoidance: Evolutionary arms race

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Lizard Snake Venom Avoidance: How Some Lizards Resist Deadly Neurotoxins from Snakes

In a recent study led by the University of Queensland, researchers have delved into the fascinating realm of how certain lizards have evolved to withstand the lethal neurotoxins produced by Australia’s most venomous snakes. This research, spearheaded by Professor Bryan Fry, focused on the interactions between venomous Australian snakes like death adders and varanid lizard species that include iconic creatures such as Komodo dragons and goannas. The findings of this study have been published in the International Journal of Molecular Sciences, shedding light on the intriguing mechanisms that enable these lizards to survive encounters with venomous snakes.

Biochemical and Physical Strategies: Varanid Lizards’ Defense Mechanisms

Professor Fry and his team uncovered that most large varanids or monitor lizards that prey on venomous snakes have inherited a remarkable trait – neurotoxin resistance. This resistance is believed to be linked to their predatory lifestyle, where they often come face to face with venomous adversaries. To simulate a natural snakebite interaction, researchers applied venoms to a specific receptor site known to be targeted by the venom. Surprisingly, not all varanid lizards employ the same defense mechanisms.

The study revealed that two lineages of giant varanids—Komodo dragons and perenties—display reduced chemical resistance to venom but rely on their physical attributes for protection. These lizards utilize their thick, bone-filled scales as armor against snakebites, and their formidable teeth to swiftly dismantle their serpent prey. This discovery highlights that for some varanids, size and mechanical defenses play a crucial role in reducing the necessity for chemical resistance, showcasing how evolution has favored physical strength over biochemical defenses.

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Evolutionary Adaptations: Losses and Gains in Venom Immunity

The research also brought to light the intriguing evolutionary adaptations observed in dwarf varanids. For instance, tree monitor lizards lost their chemical resistance as they evolved to inhabit elevated terrains away from predators. Conversely, other dwarf lineages reacquired chemical resistance as they transitioned into burrowing lifestyles. This dynamic dance of adaptation underscores the intricate evolutionary processes that shape the survival strategies of these lizards in delicate ecosystems, illustrating a continuous interplay of gains and losses over time.

Uthpala Chandrasekara, a Ph.D. candidate at UQ who conducted this research as part of her thesis, emphasized the complex nature of the evolutionary battle between Australian snakes and varanid lizards. The study highlights a biological arms race where snakes have developed potent venoms to counteract the defenses of lizards, prompting lizards to evolve in response. Chandrasekara emphasized the ever-changing nature of this predator-prey dynamic, where each evolutionary progression triggers a countermove in the opposing species.

Future Directions: Insights into Giant Lizards’ Evolutionary Strategies

Looking ahead, the research team plans to extend their investigations to related giant lizards in Africa and Asia to broaden their understanding of these captivating animals. By exploring the evolutionary adaptations of various lizard species in response to venomous snakes, researchers aim to unravel the intricate mechanisms that underpin lizard-snakе interactions across diverse habitats and regions. This ongoing research promises to unveil further insights into the evolutionary strategies employed by giant lizards to navigate the perilous world of venomous snakes, offering a glimpse into the complex and ever-evolving dynamics of predator-prey relationships in the animal kingdom.

Links to additional Resources:

1. www.uq.edu.au 2. www.venomresearchlab.org 3. www.australiangeographic.com.au

Related Wikipedia Articles

Topics: Komodo dragon, Varanid lizards, Venom resistance

Komodo dragon
The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a member of the monitor lizard family Varanidae that is endemic to the Indonesian islands of Komodo, Rinca, Flores, and Gili Motang. It is the largest extant species of lizard, growing to a maximum length of 3 m...
Read more: Komodo dragon

Varanidae
The Varanidae are a family of lizards in the superfamily Varanoidea and order Anguimorpha. The family, a group of carnivorous and frugivorous lizards, includes the living genus Varanus and a number of extinct genera more closely related to Varanus than to the earless monitor lizard (Lanthanotus). Varanus includes the Komodo...
Read more: Varanidae

Venom
Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved venom apparatus, such as fangs or a stinger, in a process called envenomation. Venom...
Read more: Venom

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